Liberation of acetic acid from lignocellulose during sterilization and its inhibitory effect on Lentinula edodes

Abstract

• Under either acidic or alkaline condition acetic anion increases in synthetic log. • Acetate inhibits significantly the mycelial growth of L. edodes . • Acetate is involved in the inhibition by lime on L. edodes . The synthetic log method for cultivating Lentinula edodes is widely practiced worldwide. However, in some synthetic logs, the cultures of L. edodes grow slowly and may even not germinate after inoculation. This phenomenon has caused serious losses in production. The acetic anion formed in synthetic logs during sterilization was investigated in this study. It was found that the pH is a key factor impacting the release of acetic anion from lignocellulose. The concentration of acetic acid increases significantly in sawdust medium under acidic or alkaline conditions compared with neutral conditions after sterilization. The highest acetic anion concentration (140.03 mmol/kg) was detected in Carya cathayensis sawdust medium at pH 2.0. In addition, the tree species of sawdust and sterilization method affect the formation of acetic acid. Acetate in sawdust medium significantly inhibits the mycelial growth of L. edodes . The inhibitory effect increases when the pH of the medium decreases. The results shed light on the improvement of cultivation techniques for L. edodes .